In the industrial treatment and mixing of corrosive reaction mixtures containing abrasive solid particles, conventionally designed mixing devices or reactors undergo considerable wear. Such reactors are therefore for example produced from standard steel and have to be equipped with acidproof cladding as well as a brickwork lining.
The reactants and the products formed in the course of the process are conventionally mixed with the aid of agitators.
The liquid reactants are normally introduced into the reactor from the top through the gas phase. Depending on the process, the solid components, which can be fine, dusty and abrasive, are initially placed in the reactor or added in the upper section thereof, and thus also first pass through the gas phase.
The known reactor designs do however have a number of considerable defects and disadvantages which restrict the manner in which the process is carried out, reduce the operative reliability of the unit concerned and result in high costs from the point of view of maintenance and servicing. Thus, the combination of materials consisting of standard steel, acidproof cladding and a brickwork lining only provides inadequate resistance to the abrasive reaction mixtures.
A further disadvantage arises when for example exothermic reactions take place in the reactor. In such cases the brick lining has an unfavourable effect since any heat of reaction liberated in the course of the reaction concerned has to be dissipated. In known bricklined reactors it is impossible to dissipate the heat of reaction via the surface of the reactor and to utilise it for example for the recovery of energy in the form of steam or hot water.
A further disadvantage is that it is only possible with difficulty and in a relatively non-reproducible manner to extract samples merely from the top of the reactor.
The known agitators used, which are usually multi-component, complicated and costly structures made of various types of materials, are comparatively susceptible to wear. Their mixing effect is also highly limited, particularly when the mixing properties of the liquid, organic and solid-containing phases are unfavourable.
If the liquid reactants are introduced into the reaction mixture via the gas phase, the differences in the density and viscosity of the phases to be mixed mean that a certain portion of the starting materials introduced remains on the interface of contact with the gas phase and does not take place in the required reaction immediately, or possibly only very slowly.
The introduction of the solid via the gas phase has the disadvantage that, especially in the case of dusty solids, fine particles are discharged with the vapour stream and are deposited in all the undesirable parts of the reactor, the agitator shaft or the downstream sections of the reactor. Such deposits form extremely compact, rigid encrustations which have an unfavourable effect on or considerably impair the production process.
The object of the invention was to provide a reactor and a mixing device which do not have the abovementioned disadvantages, allow a longer period of operation and possibly an increased service life and allow the throughput of starting materials to be increased while correspondingly modifying the method of procedure.